class UrlMappings {
    static mappings = {
        "/"{
            controller = "principal" 
            action = "home" 
        } 
        "/login/$action?"(controller: "login")
        "/logout/$action?"(controller: "logout")
        
        "/$controller/$action?/$id?"{
            constraints {
                // apply constrants here
            }
        }
	"500"(view:'/error')
    }
}